In a response provided toThe Wall Street Journal, Apple said it has been working closely for months with China Labor Watch, the group that issued the report on Pegatron. The group recently informed Apple that workers' ID cards were being withheld, which prompted the company to conduct an audit and confirm the issue, before putting a stop to Pegatron's practices.

The latest report from China Labor Watch alleges that Pegatron has been violating Chinese regulations related to workplace safety, withholding of worker pay, and sub-par living conditions. Apple has said the claims are new to the company, and they will be investigated "immediately."

"Our audit teams will return to Pegatron, RiTeng and AVY for special inspections this week," Apple's statement reads. "If our audits find that workers have been underpaid or denied compensation for any time they've worked, we will require that Pegatron reimburse them in full."

Apple noted that it has conducted 15 "comprehensive audits" of Pegatron facilities since 2007. Those have covered more than 130,000 workers.

The most recent survey conducted by Apple in June found that Pegatron employees work an average of 46 hours per week. Pegatron is just one company in Apple's massive supply chain, which comprises more than a million total employees.

Criticism of Apple's supply chain is not new, but in the past most of the scrutiny has been aimed at the company's primary supply partner, Foxconn. But this year Apple began looking to diversify its supply chain, giving a greater presence to Pegatron.